This invention relates to patterning thin films and various layers on a substrate. Such patterning includes patterning for fabricating semiconductor devices within a photolithographic patterning scheme.
In material processing methodologies (such as photolithography), creating patterned layers comprises the application of a thin layer of radiation-sensitive material, such as photoresist (resist), to an upper surface of a substrate. This radiation-sensitive material is transformed into a patterned mask that can be used to transfer a pattern into an underlying layer on a substrate such as by etching processes. Patterning of the radiation-sensitive material generally involves exposure by a radiation source through a reticle (and associated optics) onto the radiation-sensitive material using, for example, a photo-lithography system such as a scanner or stepper tool. This exposure can then be followed by the removal of irradiated regions of the radiation-sensitive material (as in the case of positive photoresist), or non-irradiated regions (as in the case of negative resist) using a developing solvent. This mask layer may comprise multiple sub-layers.
Extreme ultraviolet (EUV) photolithography is an emerging technology designed to use EUV radiation to pattern various resist films. This patterning can be part of microfabrication processes, such as those used to make integrated circuits. EUV radiation can include light spanning wavelengths from 124 nm down to around 10 nm, with EUV photolithography attempting to use wavelengths between 10-20 nm.